Aluminum is gaining in importance increasingly as material in coachbuilding. In particular, top class vehicles and sports cars are already in part produced entirely from aluminum. Despite higher costs, aluminum can compete with steel in certain areas of use. Bodies fabricated completely from aluminum can already be mass produced, the methods used for the production of aluminum components and the joining methods for connecting the individual components not, as a rule, requiring more time than is the case for steel parts. Particularly in the case of the high recycling rates to be expected on the basis of the costs of aluminum, the economic balance is also extremely advantageous in the case of aluminum bodies. The energy-intensive production can already be counterbalanced after a short period of use owing to the reductions in consumption and emission which are to be attained.
When aluminum is used in coachbuilding, however, there is at present no possibility for online monitoring of the quality of the welded joints produced, in particular of spot welds. To date, this has had to be safeguarded by a destructive sampling inspection. This procedure is expensive and time-consuming, and is always attended by a certain potential error because of the possibility of nonrepresentative samples.
It follows that there is a need for appropriate improvements in the welding of aluminum, which permit reliable statements relating to the welding quality.